Complete elimination of pathogenic micro-organisms on various surfaces, especially hard surfaces where such organisms may stay active for relatively long periods of time, has long been a goal of those charged with cleaning and maintaining in an antiseptic fashion commercial and institutional settings such as hospitals, medical clinics, meat packing and food preparation areas. A variety of chemical disinfecting agents have been developed to accomplish that goal. However, some of these agents have disadvantages in that some are corrosive or unpleasant to smell or capable of staining certain surfaces that commonly need to be cleaned and disinfected. Furthermore, some such agents are simply not effective against certain of the micro-organisms that may be found in institutional settings.
Tubercle bacilli create a significant problem in commercial and institutional settings, especially in hospitals, because of their tendency to be rather easily transmitted from one person to another. A number of researchers have reported on the efficacy of various chemical disinfecting agents to eliminate tubercle bacilli.
An article by W. A. Rutala, et al. entitled "Inactivation of Mycobacterium tuberculosis and Mycobacterium bovis by 14 hospital disinfectants" (American Journal of Medicine, vol. 91(3B), pages 267S-271S (1991)) reports that chlorine dioxide, 0.80% hydrogen peroxide plus 0.06% peroxyacetic acid and an iodophor achieved complete inactivation of both of the titled micro-organisms while two different quaternary ammonium compounds as well as 100 parts per million ("ppm") of chlorine were not effective against both micro-organisms. They reported that glutaraldehydes, a phenolic and chlorine (1,000 ppm) were completely effective against Mycobacterium tuberculosis and showed good inactivation of Mycobacterium bovis. This article reports on page 268S that Mycobacterium tuberculosis "was studied because it is a recognized human pathogen that has been associated with infections caused by ineffective disinfectants or disinfection procedures . . . and [Mycobacterium] bovis was selected because it is the organism required by the AOAC for tuberculocidal activity testing . . . ."
An article by M. Best et al. entitled "Efficacies of selected disinfectants against Mycobacterium tuberculosis" (Journal of Clinical Microbiology, vol. 28(10), pages 2234-9 (1990)) likewise reported that the quaternary ammonium compound tested (0.04% dimethyl benzylammonium chloride) was ineffective against Mycobacterium tuberculosis. It also reported that sodium hypochlorite required a higher concentration (10,000 parts per million "ppm") of available chlorine to achieve an effective level of disinfection than did sodium dichloro isocyanurate (6,000 ppm).
Chlorine bleaches such as aqueous sodium hypochlorite have long been recognized as being effective against all types of micro-organisms provided that the bleach is used in sufficiently high concentrations such as 5,000 ppm (0.5%) of active sodium hypochlorite and higher depending on the micro-organism to be eliminated. These types of solutions are recommended for use for disinfecting an area where blood or other potentially pathogenic biological contaminants have been spilled or released and total disinfection is required. At such high levels of sodium hypochlorite, the chlorine smell from the bleach simply makes this agent undesirable for routine cleaning and disinfection of, for example, hospital rooms, where patients remain in the room during and after the cleaning and disinfection process.
A sterilization system based on a chlorine bleach disinfecting agent that uses two baths in which articles to be sterilized are placed is described in U.S. Pat. No. 4,418,055 to Andersen et al. In this system, the ingredients used in the sterilization system are stored in hermetically sealed bags that keep reactive ingredients away from each other until use. The bags also provide premeasured quantities of the ingredients to avoid any errors that might be caused by having the user measure out each component needed.
Quaternary ammonium compounds have long been recognized as being useful for their antibacterial properties as can be seen from U.S. Pat. No. 3,836,669 to Dadekian; U.S. Pat. No. 4,320,147 to Schaeufele; U.S. Pat. No. 4,336,151 to Like et al.; U.S. Pat. No. 4,444,790 to Green et al.; U.S. Pat. No. 4,464,398 to Sheets et al.; and U.S. Pat. No. 4,540,505 to Frazier.
Higher levels of quaternary ammonium compounds have been reported as being effective disinfectants against various pathogenic micro-organisms, even including Mycobacterium tuberculosis. J. Dos Reis Meirelles Neto et al. report in their article entitled "Tuberculocidal activity of some cationic detergents" ("Atividade tuberculocida de alguns detergentes cationicos")--Folha Med., vol. 87(4), pages 227-232 (1983)--that the quaternary ammonium salts benzalkonium chloride, ammonium-alkyl-dimethylbenzyl chloride plus ammonium-alkyl-dimethylethyl-benzyl chloride and cetylpyridinium chloride in a concentration of 0.4% showed microbiocidal action to sputum microbial flora and some toxic effect to Mycobacterium tuberculosis.
Another article by L. Szymaczek-Meyer et al. entitled "Effect of some disinfectants (phenol derivatives, quaternary ammonium compounds, aldehydes and chloramine) on human type tubercle bacilli sensitive and resistant to antibacillary drugs" (Med. Dosw. Mikrobiol, vol. 31(1), pages 53-59 (1979)) reported the results of using commercial concentrations of available hospital disinfectants on dense suspensions of tubercle bacilli strain Hsub 3sub 7Rv and human type wild strains sensitive and resistant to antibacillary drugs. They found that some of the disinfectants checked were tuberculocidal, but generally used solutions containing at least about 0.6% active disinfecting agent.
To minimize expense, undesirable odors and possible detrimental effects of disinfecting agents on surfaces to be disinfected, it is desirable to minimize the amount of disinfecting agents used while still retaining efficacy against pathogenic micro-organisms, especially against tubercle bacilli such as Mycobacterium tuberculosis. As will be explained in greater detail below, I have found that a combination of a specific amount of a chlorine bleach compound such as sodium dichloro isocyanurate with a specific amount of a bactericidal quaternary ammonium compound provides a composition that is effective against tubercle bacilli even though the concentration of the each compound used, when evaluated individually at that concentration, is ineffective against tubercle bacilli.
In the past, combinations of chlorine or peroxygen bleaches with quaternary ammonium compounds have been taught, but for different purposes or at different use levels than I have discovered. Typically, a relatively large amount of chlorine bleach (0.5% to 1% or more of active bleach compound which is 5,000 to 10,000 ppm of active bleach compound) has been combined with cationic surfactants (which typically refer to quaternary ammonium compounds generally and not all of these compounds possess bactericidal or disinfectant properties). If a sufficiently high amount of bleach compound is used (i.e., that, by itself, is capable of destroying pathogenic micro-organisms, including tubercle bacilli), then there is no need to include a bactericidal quaternary ammonium compound for disinfection purposes.
U.S. Pat. No. 3,669,891 to Greenwood et al. teaches various compositions that emit visible light during use. Example 8 teaches a two-component air freshener/germicidal composition that comprises a combination of an aqueous sodium hypochlorite solution (0.5% available chlorine) and a second solution containing 1% cetyl trimethylammonium bromide and 1.5% oleyl di-betahydroxyethyl methylammonium methosulfate. The two solutions were combined in the nozzle of a two compartment pump spray package set to deliver equal quantities of liquid from each compartment. Thus, the level of all quaternary ammonium compounds alone in the mixed liquids was 0.75% or 7,500 ppm of active material.
U.S. Pat. No. 2,987,435 to Davies et al. teaches synergistically active germicidal materials and methods for cleaning and disinfecting materials by combining a hypochlorite with a quaternary ammonium compound. One such method involves contacting a surface with a composition containing sodium hypochlorite at an available chlorine level of 0.45% to 5%, followed by contacting the surface with an aqueous solution of benzalkonium chloride (0.05% to 5.0% by weight, preferably 0.02%). Another method involves applying a solution comprising about 0.45% to about 5% by weight of available chlorine and from about 0.5% to 5% of benzalkonium chloride. Davies et al. teaches that the active materials are added such that the composition contains the equivalent of at least 0.1% by weight of available chlorine and 0.01% by weight of quaternary ammonium salt. Preferably, the compositions contain from 0.1% to 5% by weight of available chlorine and from 0.05 to 20 parts of quaternary ammonium salt are incorporated for each part by weight of chlorine. Davies et al. teaches that a concentrated aqueous germicidal solution can be made that is a solution of aqueous sodium hypochlorite solution containing from 0.25% to 1.5% available chlorine to which is added from 2.5% to 7.5% of a quaternary ammonium salt to form a concentrate and thereafter the concentrate is diluted 40-fold to obtain a germicidal bleaching solution.
U.S. Pat. No. 3,852,210 to Krezanoski teaches a stable liquid detergent containing active oxygen for use as a bleaching and cleaning composition, particularly for the skin. It contains from 0.1% to 50% of detergent vehicle-soluble peroxygen compounds as the active ingredient and, optionally, from 0.01% to 10% of a quaternary ammonium surfactive agent. The latter are added for the purpose of increasing detergency and foam stability as well as for imparting residual germicidal activity. U.S. Pat. No. 4,169,065 to Robertson teaches an ear cleaning mixture for canines containing a mixture of alcohol, acetic acid, hydrogen peroxide (0.3% to 3%), (soap) benzethonium chloride (0.01% to 0.06%), and water. Neither of these patents suggest the use of chlorine bleaches.
Cleaning compositions which may contain bleach compounds plus organosilicon quaternary ammonium compounds (to provide residual antibacterial activity to surfaces cleaned with such compositions) are taught in U.S. Pat. No. 4,783,283 to Stoddart (alkali metal hypochlorite level of from 1% to 12%); U.S. Pat. No. 4,576,728 to Stoddart (alkali metal hypochlorite level of from 1% to 12%); and U.S. Pat. No. 4,005,028 to Heckert et al. (any chlorine yielding bleach wherein the available chlorine content of the cleaning composition ranges from 0.5% to 10%). These patents do not suggest the use of organic quaternary ammonium compounds that are free of silicon.
Stable perfumed or thickened chlorine bleach compositions which may contain quaternary ammonium compounds are known. U.S. Pat. Nos. 4,113,645 to DeSimone teaches aqueous household bleach compositions containing from 5% to 15% of sodium hypochlorite along with 0.025% to 1% (based on the weight of the aqueous bleach composition) of a quaternary ammonium salt where the latter is to help disperse a perfume oil within the bleach composition to mask the smell of the household bleach composition.
U.S. Pat. No. 5,080,826 to Colborn et al. teaches stable fragranced household bleach compositions in which an immiscible or slightly miscible fragrance is dispersed in the bleach without wetting the interior walls of the plastic bleach container. Colborn et al. teach that 0-100 ppm of various surfactants can be used to disperse the fragrance within the bleach composition, wherein such surfactants include quaternary ammonium compounds.
British Patent No. 1,466,560 to Jeyes Group Ltd. teaches thickened aqueous solutions of alkali metal hypochlorites (1% to 14% available chlorine) for use in cleaning and disinfecting various surfaces, especially vertical surfaces. A combination of an alkali metal sarcosinate surfactant with another surfactant that can include quaternary ammonium compounds are useful as the thickening agents. British Pat. No. 1,548,379 to Jeyes Group Ltd. is similar to the '560 Patent except it uses a thickening agent for aqueous solutions of alkali metal hypochlorites composed of a sucrose surfactant and one or more other surfactants that are soluble in the hypochlorite, including quaternary ammonium compounds.
U.S. Pat. No. 4,264,466 to Carleton et al. teaches mulls consisting of a liquid phase and a dispersed solid phase. The mulls can be used as detergents and may include water sensitive detergency adjuvants such as bleaches as well as cationic surfactants. Some of the cationics are said to be able to provide sanitization of the washload, but are primarily useful as suspension agents for the dispersed solids.
U.S. Pat. No. 4,461,652 to Richmond teaches process and product for removing barnacles from marine vessels that is composed of a stock mixture of (1) 15% to 35% hydrocarbon liquid; (2) 1.5% to 6% of surfactant that can include the alkyl, dialkylbenzylammonium salt of (5) below; (3) 0% to 2% alcohol; (4) 0.5% to 5% metal hypochlorite; (5) 0.5 to 1.5% alkyl, dialkylbenzylammonium salt; (6) 30% to 50% water; and 52.5% to 0.5% inert carriers. The stock mixture may be diluted substantially 1:1 with water prior to use.